If it is less than 99.99% pure copper, what are the other alloying elements?

You add oxygen to copper to reduce other impurities. The 5-9's stuff is BS for the purpose of a wire and hype sold to idiots. Almost all copper will contain lead, tin, zinc, arsenic, and several other metals. It comes out of the earth and was made in stars.

When you need to send a few microvolts over several hundred feet, then let's talk about the metal. Actually, I will inform you we invented these things called amplifiers.

You add oxygen to copper to reduce other impurities. The 5-9's stuff is BS for the purpose of a wire and hype sold to idiots. Almost all copper will contain lead, tin, zinc, arsenic, and several other metals. It comes out of the earth and was made in stars.

When you need to send a few microvolts over several hundred feet, then let's talk about the metal. Actually, I will inform you we invented these things called amplifiers.